In the Ethernet communication network used in a vehicle (Ethernet: a registered trademark), a layer-2 switching hub used as a network switch (i.e., may simply be designated as a “switch” in the following) does not have a Media Access Control (MAC) address nor an Internet Protocol (IP) address, in general. Therefore, it is difficult to identify an individual switching hub.
Further, unless each of switching hubs is individually identifiable, a master device of the communication network cannot instruct each of the switching hubs to perform a certain/desired process (e.g., cannot instruct an individual switch to overwrite a configuration setting) to read fault information.
To resolve such a problem, a layer-3 switch may be used, for example (i.e., use of a switching hub having a static Identification (ID) address), which leads to a complicated ID number management system, and also leads to an increase of the management cost. Further, the layer-3 switch itself is more expensive, compared with the layer-2 switch (i.e., a switching hub of layer-2).
For example, a technology for distributing frame data by using plural switching nodes is described in a patent document, JP 2011-249979 A (patent document 1).
In the technology of the patent document 1, a dynamic assignment of an identifier to a switching hub that does not have any identifier is not performable. Therefore, sending an instruction to each of the individual switching hubs is not possible.